Step I HCM: systolic dysfunction vs. diastolic

[NCF145]

In FA it lists HCM as a diastolic dysfunction. In RR Path it describes HCM as a systolic dysfunction. I'm guessing this means that HCM can result in both diastolic and systolic dysfunction, but it is the degree of obstruction by the IV septum and anterior mitral valve leaflet that determines whether or not there is systolic dysfunction. Does that sound about right?

 

[rahulb]

its a diastolic (filling) dysfunction with a systolic murmur

 

[NCF145]

its a diastolic (filling) dysfunction with a systolic murmur

Thanks. I completely misread RR last night. Guess that is what happens when you study half asleep.

 

[sebsvenmdc]

In FA it lists HCM as a diastolic dysfunction. In RR Path it describes HCM as a systolic dysfunction. I'm guessing this means that HCM can result in both diastolic and systolic dysfunction, but it is the degree of obstruction by the IV septum and anterior mitral valve leaflet that determines whether or not there is systolic dysfunction. Does that sound about right?

I think you're right about it being a combo problem though. I mean, the LV outflow obstruction can drastically affect LV CO...and that has to be considered systolic dysfunction. Also, part of the treatment, beta blockers, while improving the filling of the LV (and addressing the diastolic dysfunction), they also address the outflow obstruction problem by increasing the distance between the thickened IV septum and the MV's anterior leaflet. Ha, I don't know if this is helpful...the fact that you asked this shows a good understanding of the problems involved.

 

[sgod34]

I think it's actually a diastolic (late) murmur or I guess atrial systole murmur. It's on FA 2009 pg 248. Both S3 and S4 happen during diastolic ventricular filling. S3 is heard immediately after the isovolumetric relaxation in diastole when the mitral valve opens. It's due to the increased filling pressure of the LV. I think the confusing part is that it's a systolic dysfunction, but causes a diastolic murmur. The murmur is heard due to the filling of the dilated LV, while the systolic dysfunction occurs due to pump failure caused by a weakened/dilated LV and the increased preload in the LV. S4 is heard at the end of diastole right before the mitral valve closed, due to the atrial kick caused by the outflow tract obstruction caused by the LA pushing against the hypertrophic LV.

- Dilated Cardiomyopathy = S3 (heard in early diastole), Systolic Df -->
PUMP FAILURE
- Hypertrophic Cardiomyopathy = S4 (heard in late diastole), Diastolic Df-->
OUTFLOW TRACT OBSTRUCTION

 

[sebsvenmdc]

I think it's actually a diastolic (late) murmur or I guess atrial systole murmur. It's on FA 2009 pg 248. Both S3 and S4 happen during diastolic ventricular filling. S3 is heard immediately after the isovolumetric relaxation in diastole when the mitral valve opens. It's due to the increased filling pressure of the LV. I think the confusing part is that it's a systolic dysfunction, but causes a diastolic murmur. The murmur is heard due to the filling of the dilated LV, while the systolic dysfunction occurs due to pump failure caused by a weakened/dilated LV and the increased preload in the LV. S4 is heard at the end of diastole right before the mitral valve closed, due to the atrial kick caused by the outflow tract obstruction caused by the LA pushing against the hypertrophic LV.

- Dilated Cardiomyopathy = S3 (heard in early diastole), Systolic Df -->
PUMP FAILURE
- Hypertrophic Cardiomyopathy = S4 (heard in late diastole), Diastolic Df-->
OUTFLOW TRACT OBSTRUCTION

Lol, we're really beating this thing into the ground. The systolic dysfunction is primarily due to MV outflow obstruction. The ventricle is hypertrophied...I think if it was dilated, that would get around the outflow obstruction problem. The reason why beta blockers and CCBs work is directly because of LV dilation that occurs with increased filling. This increases the distance between the MV anterior leaflet and the IV septum, and allows more blood flow before obstruction occurs.